Related

New Functionality for Version 4

A flexible definition of elastic material data enables the
solid mechanics interfaces to support bulk modulus and shear modulus,
Lamé constants, and pressure-wave and shear-wave speed in addition to
Young’s modulus and Poisson’s ratio.

Custom hyperelastic material models can be created by
specifying a strain energy function in terms of deformation tensor
components and invariants.

A flexible 2D solid mechanics interface allows you to switch
between plane stress and plane strain approximations at any point
during modeling. For example, it is now easy to compare the results
with plane strain and plane stress assumptions.

Prescribed velocity and acceleration boundary conditions are
now available also in transient analysis. Previously, these conditions
were available only in the frequency domain.

A new rigid connector boundary condition (only in 3D in
version 4.0) makes it possible to apply kinematic constraints, forces,
and moments on boundaries assumed to displace as a rigid body.

A new 3D shell and 2D plate element formulations based on
first-order or second-order Lagrange shape functions on both triangles
and quadrilaterals gives improved accuracy. Curved surfaces and mixed
solid-shell models, in particular, are improved. In addition, the new
shell elements are fully multiphysics-enabled and support large
deformations and anisotropic materials.

The Elastoplastic Material Model
now allows the use of a non associated flow rule.

Backward Compatibility

Cross-Section Library

The cross-section library for beams is not available in
version 4.0a. This is planned for version 4.1.

Plane Stress

Version 4 represents the out-of-plane strain as a separate degree of
freedom. Plane stress models made with version 3.5a need
to be re-solved to correctly compute strains and stresses. Displacements
are correctly computed.

Symbols

Symbols in the graphics window representing constraints and
loads are not yet available in version 4.0a. Symbols will be available
in version 4.1.

Iterative solver used in 3D by default

GMRES/GMG with LU preconditioner is the default solver in version
4.0a for 3D static and time dependent studies.

For stretched elements, this solver may run into convergence
problems. If you run into convergence problems, try to improve the
quality of the tetrahedral mesh by reducing the variations in mesh size.
For smaller and medium-size problems, switch to a direct solver.